Hi.
Thanks for your query.
Noted the history and understood the concerns.
Since there is projectile
vomiting after exposure to sun in a child of 4 and 1/2 year old the most probable reason I can think of is increase in intracranial tension. Other causes of vomiting should also be considered.
Hence I would advise you the following in such a situation:
Get him to the
Pediatrician for clinical evaluation, examination and investigations:
Blood for CBC, liver functions,
thyroid and other functions as needed.
CT scan or MRI of the brain.
Tests of urine and stool.
If needed a
second opinion of a Gastroenterologist and
Neurologist as there is a projectile vomiting on exposure to sun which in itself is uncommon.
All these things will lead to a proper diagnosis as soon as possible and thus getting a plan of proper management.